Stray light suppression for head worn computing

ABSTRACT

Aspects of the present disclosure relate to head worn computing lighting systems and stray light control.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to and is a continuationof the following U.S. patent application, which is hereby incorporatedby reference in its entirety:

U.S. non-provisional application Ser. No. 14/163,646, entitledPERIPHERAL LIGHTING FOR HEAD WORN COMPUTING, filed Jan. 24, 2014.

BACKGROUND

1. Field of the Invention

This invention relates to head worn computing. More particularly, thisinvention relates to stray light suppression systems used in head worncomputing.

2. Description of Related Art

Wearable computing systems have been developed and are beginning to becommercialized. Many problems persist in the wearable computing fieldthat need to be resolved to make them meet the demands of the market.

SUMMARY

Aspects of the present invention relate to stray light control systemsin head worn computing.

These and other systems, methods, objects, features, and advantages ofthe present invention will be apparent to those skilled in the art fromthe following detailed description of the preferred embodiment and thedrawings. All documents mentioned herein are hereby incorporated intheir entirety by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described with reference to the following Figures. Thesame numbers may be used throughout to reference like features andcomponents that are shown in the Figures:

FIG. 1 illustrates a head worn computing system in accordance with theprinciples of the present invention.

FIG. 2 illustrates a head worn computing system with optical system inaccordance with the principles of the present invention.

FIG. 3 a illustrates a prior art upper optical module with a DLP imagesource.

FIG. 3 b illustrates an upper optical module that uses polarized lightin accordance with the principles of the present invention.

FIG. 4 illustrates an upper optical module in accordance with theprinciples of the present invention

FIG. 4 a illustrates an example geometry of a TIR wedge and a correctingwedge in an upper optical module in accordance with principles of thepresent invention.

FIG. 5 illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 5 a illustrates an example geometry of a TIR wedge, a correctingwedge and an off light redirection wedge in an upper optical module inaccordance with principles of the present invention.

FIG. 6 illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 7 illustrates angles of combiner elements in accordance with theprinciples of the present invention.

FIG. 8 illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 9 illustrates an eye imaging system in accordance with theprinciples of the present invention.

FIG. 10 illustrates a light source in accordance with the principles ofthe present invention.

FIG. 10 a illustrates a structure in a backlight for redirecting andcollimating light provided by the backlight to an upper optical modulein accordance with principles of the present invention.

FIG. 10 b illustrates another structure in a backlight for redirectingand collimating light provided by the backlight to an upper opticalmodule in accordance with principles of the present invention.

FIG. 11 a illustrates a narrow band light source in accordance with theprinciples of the present invention.

FIG. 11 b is a spectral graph for light provided by example red, greenand blue LEDs.

FIG. 11 c is a transmission graph for an example trisimulus notch filterincluded in the narrow band light source in accordance with principlesof the present invention.

FIG. 11 d is a spectral graph of the narrow bands of light provided bythe light source of FIG. 11 a in accordance with principles of thepresent invention.

FIG. 12 illustrates a light source in accordance with the principles ofthe present invention.

FIG. 12 a is an intensity vs wavelength chart showing the effect of UVillumination on an example quantum dot.

FIG. 12 b is an intensity vs wavelength chart showing the emissions ofexample red, green and blue quantum dots.

FIG. 13 a illustrates a peripheral lighting effects system according tothe principles of the present invention.

FIG. 13 b illustrates a peripheral lighting effects system according tothe principles of the present invention.

FIG. 13 c illustrates a peripheral lighting effects system according tothe principles of the present invention.

FIG. 14 a illustrates an eye cover according to the principles of thepresent invention.

FIG. 14 b illustrates an eye cover according to the principles of thepresent invention.

FIG. 14 c illustrates an eye cover according to the principles of thepresent invention.

While the invention has been described in connection with certainpreferred embodiments, other embodiments would be understood by one ofordinary skill in the art and are encompassed herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Aspects of the present invention relate to head-worn computing (“HWC”)systems. HWC involves, in some instances, a system that mimics theappearance of head-worn glasses or sunglasses. The glasses may be afully developed computing platform, such as including computer displayspresented in each of the lenses of the glasses to the eyes of the user.In embodiments, the lenses and displays may be configured to allow aperson wearing the glasses to see the environment through the lenseswhile also seeing, simultaneously, digital imagery, which forms anoverlaid image that is perceived by the person as a digitally augmentedimage of the environment, or augmented reality (“AR”).

HWC involves more than just placing a computing system on a person'shead. The system may need to be designed as a lightweight, compact andfully functional computer display, such as wherein the computer displayincludes a high resolution digital display that provides a high level ofemersion comprised of the displayed digital content and the see-throughview of the environmental surroundings. User interfaces and controlsystems suited to the HWC device may be required that are unlike thoseused for a more conventional computer such as a laptop. For the HWC andassociated systems to be most effective, the glasses may be equippedwith sensors to determine environmental conditions, geographic location,relative positioning to other points of interest, objects identified byimaging and movement by the user or other users in a connected group,and the like. The HWC may then change the mode of operation to match theconditions, location, positioning, movements, and the like, in a methodgenerally referred to as a contextually aware HWC. The glasses also mayneed to be connected, wirelessly or otherwise, to other systems eitherlocally or through a network. Controlling the glasses may be achievedthrough the use of an external device, automatically throughcontextually gathered information, through user gestures captured by theglasses sensors, and the like. Each technique may be further refineddepending on the software application being used in the glasses. Theglasses may further be used to control or coordinate with externaldevices that are associated with the glasses.

Referring to FIG. 1, an overview of the HWC system 100 is presented. Asshown, the HWC system 100 comprises a HWC 102, which in this instance isconfigured as glasses to be worn on the head with sensors such that theHWC 102 is aware of the objects and conditions in the environment 114.In this instance, the HWC 102 also receives and interprets controlinputs such as gestures and movements 116. The HWC 102 may communicatewith external user interfaces 104. The external user interfaces 104 mayprovide a physical user interface to take control instructions from auser of the HWC 102 and the external user interfaces 104 and the HWC 102may communicate bi-directionally to affect the user's command andprovide feedback to the external device 108. The HWC 102 may alsocommunicate bi-directionally with externally controlled or coordinatedlocal devices 108. For example, an external user interface 104 may beused in connection with the HWC 102 to control an externally controlledor coordinated local device 108. The externally controlled orcoordinated local device 108 may provide feedback to the HWC 102 and acustomized GUI may be presented in the HWC 102 based on the type ofdevice or specifically identified device 108. The HWC 102 may alsointeract with remote devices and information sources 112 through anetwork connection 110. Again, the external user interface 104 may beused in connection with the HWC 102 to control or otherwise interactwith any of the remote devices 108 and information sources 112 in asimilar way as when the external user interfaces 104 are used to controlor otherwise interact with the externally controlled or coordinatedlocal devices 108. Similarly, HWC 102 may interpret gestures 116 (e.g.captured from forward, downward, upward, rearward facing sensors such ascamera(s), range finders, IR sensors, etc.) or environmental conditionssensed in the environment 114 to control either local or remote devices108 or 112.

We will now describe each of the main elements depicted on FIG. 1 inmore detail; however, these descriptions are intended to provide generalguidance and should not be construed as limiting. Additional descriptionof each element may also be further described herein.

The HWC 102 is a computing platform intended to be worn on a person'shead. The HWC 102 may take many different forms to fit many differentfunctional requirements. In some situations, the HWC 102 will bedesigned in the form of conventional glasses. The glasses may or may nothave active computer graphics displays. In situations where the HWC 102has integrated computer displays the displays may be configured assee-through displays such that the digital imagery can be overlaid withrespect to the user's view of the environment 114. There are a number ofsee-through optical designs that may be used, including ones that have areflective display (e.g. LCoS, DLP), emissive displays (e.g. OLED, LED),hologram, TIR waveguides, and the like. In addition, the opticalconfiguration may be monocular or binocular. It may also include visioncorrective optical components. In embodiments, the optics may bepackaged as contact lenses. In other embodiments, the HWC 102 may be inthe form of a helmet with a see-through shield, sunglasses, safetyglasses, goggles, a mask, fire helmet with see-through shield, policehelmet with see through shield, military helmet with see-through shield,utility form customized to a certain work task (e.g. inventory control,logistics, repair, maintenance, etc.), and the like.

The HWC 102 may also have a number of integrated computing facilities,such as an integrated processor, integrated power management,communication structures (e.g. cell net, WiFi, Bluetooth, local areaconnections, mesh connections, remote connections (e.g. client server,etc.)), and the like. The HWC 102 may also have a number of positionalawareness sensors, such as GPS, electronic compass, altimeter, tiltsensor, IMU, and the like. It may also have other sensors such as acamera, rangefinder, hyper-spectral camera, Geiger counter, microphone,spectral illumination detector, temperature sensor, chemical sensor,biologic sensor, moisture sensor, ultrasonic sensor, and the like.

The HWC 102 may also have integrated control technologies. Theintegrated control technologies may be contextual based control, passivecontrol, active control, user control, and the like. For example, theHWC 102 may have an integrated sensor (e.g. camera) that captures userhand or body gestures 116 such that the integrated processing system caninterpret the gestures and generate control commands for the HWC 102. Inanother example, the HWC 102 may have sensors that detect movement (e.g.a nod, head shake, and the like) including accelerometers, gyros andother inertial measurements, where the integrated processor mayinterpret the movement and generate a control command in response. TheHWC 102 may also automatically control itself based on measured orperceived environmental conditions. For example, if it is bright in theenvironment the HWC 102 may increase the brightness or contrast of thedisplayed image. In embodiments, the integrated control technologies maybe mounted on the HWC 102 such that a user can interact with itdirectly. For example, the HWC 102 may have a button(s), touchcapacitive interface, and the like.

As described herein, the HWC 102 may be in communication with externaluser interfaces 104. The external user interfaces may come in manydifferent forms. For example, a cell phone screen may be adapted to takeuser input for control of an aspect of the HWC 102. The external userinterface may be a dedicated UI, such as a keyboard, touch surface,button(s), joy stick, and the like. In embodiments, the externalcontroller may be integrated into another device such as a ring, watch,bike, car, and the like. In each case, the external user interface 104may include sensors (e.g. IMU, accelerometers, compass, altimeter, andthe like) to provide additional input for controlling the HWD 104.

As described herein, the HWC 102 may control or coordinate with otherlocal devices 108. The external devices 108 may be an audio device,visual device, vehicle, cell phone, computer, and the like. Forinstance, the local external device 108 may be another HWC 102, whereinformation may then be exchanged between the separate HWCs 108.

Similar to the way the HWC 102 may control or coordinate with localdevices 106, the HWC 102 may control or coordinate with remote devices112, such as the HWC 102 communicating with the remote devices 112through a network 110. Again, the form of the remote device 112 may havemany forms. Included in these forms is another HWC 102. For example,each HWC 102 may communicate its GPS position such that all the HWCs 102know where all of HWC 102 are located.

FIG. 2 illustrates a HWC 102 with an optical system that includes anupper optical module 202 and a lower optical module 204. While the upperand lower optical modules 202 and 204 will generally be described asseparate modules, it should be understood that this is illustrative onlyand the present invention includes other physical configurations, suchas that when the two modules are combined into a single module or wherethe elements making up the two modules are configured into more than twomodules. In embodiments, the upper module 202 includes a computercontrolled display (e.g. LCoS, DLP, OLED, etc.) and image light deliveryoptics. In embodiments, the lower module includes eye delivery opticsthat are configured to receive the upper module's image light anddeliver the image light to the eye of a wearer of the HWC. In FIG. 2, itshould be noted that while the upper and lower optical modules 202 and204 are illustrated in one side of the HWC such that image light can bedelivered to one eye of the wearer, that it is envisioned by the presentinvention that embodiments will contain two image light deliverysystems, one for each eye.

FIG. 3 b illustrates an upper optical module 202 in accordance with theprinciples of the present invention. In this embodiment, the upperoptical module 202 includes a DLP computer operated display 304 whichincludes pixels comprised of rotatable mirrors, polarized light source302, ¼wave retarder film 308, reflective polarizer 310 and a field lens312. The polarized light source 302 provides substantially uniform lightthat is generally directed towards the reflective polarizer 310. Thereflective polarizer reflects light of one polarization state (e.g. Spolarized light) and transmits light of the other polarization state(e.g. P polarized light). The polarized light source 302 and thereflective polarizer 310 are oriented so that the polarized light fromthe polarized light source 302 reflected generally towards the DLP 304.The light then passes through the ¼wave film 308 once beforeilluminating the pixels of the DLP 304 and then again after beingreflected by the pixels of the DLP 304. In passing through the ¼wavefilm 308 twice, the light is converted from one polarization state tothe other polarization state (e.g. the light is converted from S to Ppolarized light). The light then passes through the reflective polarizer310. In the event that the DLP pixel(s) are in the “on” state (i.e. themirrors are positioned to reflect light back towards the field lens 312,the “on” pixels reflect the light generally along the optical axis andinto the field lens 312. This light that is reflected by “on” pixels andwhich is directed generally along the optical axis of the field lens 312will be referred to as image light 316. The image light 316 then passesthrough the field lens to be used by a lower optical module 204.

The light that is provided by the polarized light source 302, which issubsequently reflected by the reflective polarizer 310 before itreflects from the DLP 304, will generally be referred to as illuminationlight. The light that is reflected by the “off” pixels of the DLP 304 isreflected at a different angle than the light reflected by the ‘on”pixels, so that the light from the “off” pixels is generally directedaway from the optical axis of the field lens 312 and toward the side ofthe upper optical module 202 as shown in FIG. 3. The light that isreflected by the “off” pixels of the DLP 304 will be referred to as darkstate light 314.

The DLP 304 operates as a computer controlled display and is generallythought of as a MEMs device. The DLP pixels are comprised of smallmirrors that can be directed. The mirrors generally flip from one angleto another angle. The two angles are generally referred to as states.When light is used to illuminate the DLP the mirrors will reflect thelight in a direction depending on the state. In embodiments herein, wegenerally refer to the two states as “on” and “off,” which is intendedto depict the condition of a display pixel. “On” pixels will be seen bya viewer of the display as emitting light because the light is directedalong the optical axis and into the field lens and the associatedremainder of the display system. “Off” pixels will be seen by a viewerof the display as not emitting light because the light from these pixelsis directed to the side of the optical housing and into a light dumpwhere the light is absorbed. The pattern of “on” and “off” pixelsproduces image light that is perceived by a viewer of the display as acomputer generated image. Full color images can be presented to a userby sequentially providing illumination light with complimentary colorssuch as red, green and blue. Where the sequence is presented in arecurring cycle that is faster than the user can perceive as separateimages and as a result the user perceives a full color image comprisedof the sum of the sequential images. Bright pixels in the image areprovided by pixels that remain in the “on” state for the entire time ofthe cycle, while dimmer pixels in the image are provided by pixels thatswitch between the “on” state and “off” state within the time of thecycle.

FIG. 3 a shows an illustration of a system for a DLP 304 in which theunpolarized light source 350 is pointed directly at the DLP 304. In thiscase, the angle required for the illumination light is such that thefield lens 352 must be positioned substantially distant from the DLP 304to avoid the illumination light from being clipped by the field lens352. The large distance between the field lens 352 and the DLP 304 alongwith the straight path of the dark state light 352, means that the lighttrap for the dark state light 352 is located at a substantial distancefrom the DLP. For these reasons, this configuration is larger in sizecompared to the upper optics module 202 of the preferred embodiments.

The configuration illustrated in FIG. 3 b can be lightweight and compactsuch that it fits into a portion of a HWC. For example, the uppermodules 202 illustrated herein can be physically adapted to mount in anupper frame of a HWC such that the image light can be directed into alower optical module 204 for presentation of digital content to awearer's eye. The package of components that combine to generate theimage light (i.e. the polarized light source 302, DLP 304, reflectivepolarizer 310 and ¼ wave film 308) is very light and is compact. Theheight of the system, excluding the field lens, may be less than 8 mm.The width (i.e. from front to back) may be less than 8 mm. The weightmay be less than 2 grams. The compactness of this upper optical module202 allows for a compact mechanical design of the HWC and the lightweight nature of these embodiments help make the HWC lightweight toprovide for a HWC that is comfortable for a wearer of the HWC.

The configuration illustrated in FIG. 3 b can produce sharp contrast,high brightness and deep blacks, especially when compared to LCD or LCoSdisplays used in HWC. The “on” and “off” states of the DLP provide for astrong differentiator in the light reflection path representing an “on”pixel and an “off” pixel. As will be discussed in more detail below, thedark state light from the “off” pixel reflections can be managed toreduce stray light in the display system to produce images with highcontrast.

FIG. 4 illustrates another embodiment of an upper optical module 202 inaccordance with the principles of the present invention. This embodimentincludes a light source 404, but in this case, the light source canprovide unpolarized illumination light. The illumination light from thelight source 404 is directed into a TIR wedge 418 such that theillumination light is incident on an internal surface of the TIR wedge418 (shown as the angled lower surface of the TRI wedge 418 in FIG. 4)at an angle that is beyond the critical angle as defined by Eqn 1.Critical angle=arc-sin(1/n)  Eqn 1

Where the critical angle is the angle beyond which the illuminationlight is reflected from the internal surface when the internal surfacecomprises an interface from a solid with a higher refractive index toair with a refractive index of 1 (e.g. for an interface of acrylic, witha refractive index of 1.5, to air, the critical angle is 41.8 degrees;for an interface of polycarbonate, with a refractive index of 1.59, toair the critical angle is 38.9 degrees). Consequently, the TIR wedge 418is associated with a thin air gap 408 along the internal surface tocreate an interface between a solid with a higher refractive index andair. By choosing the angle of the light source 404 relative to the DLP402 in correspondence to the angle of the internal surface of the TIRwedge 418, illumination light is turned toward the DLP 402 at an anglesuitable for providing image light as reflected from “on” pixels.Wherein, the illumination light is provided to the DLP 402 atapproximately twice the angle of the pixel mirrors in the DLP 402 thatare in the “on” state, such that after reflecting from the pixelmirrors, the image light is directed generally along the optical axis ofthe field lens. Depending on the state of the DLP pixels, theillumination light from “on” pixels may be reflected as image light 414which is directed towards a field lens and a lower optical module 204,while illumination light reflected from “off” pixels (dark state light)is directed in a separate direction 410, which may be trapped and notused for the image that is ultimately presented to the wearer's eye.

The light trap may be located along the optical axis defined by thedirection 410 and in the side of the housing, with the function ofabsorbing the dark state light. To this end, the light trap may becomprised of an area outside of the cone of image light from the “on”pixels. The light trap is typically madeup of materials that absorblight including coatings of black paints or other light absorbing toprevent light scattering from the dark state light degrading the imageperceived by the user. In addition, the light trap may be recessed intothe wall of the housing or include masks or guards to block scatteredlight and prevent the light trap from being viewed adjacent to thedisplayed image.

The embodiment of FIG. 4 also includes a corrective wedge 420 to correctthe effect of refraction of the image light 414 as it exits the TIRwedge 418. By including the corrective wedge 420 and providing a thinair gap 408 (e.g. 25 micron), the image light from the “on” pixels canbe maintained generally in a direction along the optical axis of thefield lens so it passes into the field lens and the lower optical module204. As shown in FIG. 4, the image light from the “on” pixels exits thecorrective wedge 420 generally perpendicular to the surface of thecorrective wedge 420 while the dark state light exits at an obliqueangle. As a result, the direction of the image light from the “on”pixels is largely unaffected by refraction as it exits from the surfaceof the corrective wedge 420. In contrast, the dark state light issubstantially changed in direction by refraction when the dark statelight exits the corrective wedge 420.

The embodiment illustrated in FIG. 4 has the similar advantages of thosediscussed in connection with the embodiment of FIG. 3 b. The dimensionsand weight of the upper module 202 depicted in FIG. 4 may beapproximately 8×8 mm with a weight of less than 3 grams. A difference inoverall performance between the configuration illustrated in FIG. 3 band the configuration illustrated in FIG. 4 is that the embodiment ofFIG. 4 doesn't require the use of polarized light as supplied by thelight source 404. This can be an advantage in some situations as will bediscussed in more detail below (e.g. increased see-through transparencyof the HWC optics from the user's perspective). An addition advantage ofthe embodiment of FIG. 4 compared to the embodiment shown in FIG. 3 b isthat the dark state light (shown as DLP off light 410) is directed at asteeper angle away from the optical axis due to the added refractionencountered when the dark state light exits the corrective wedge 420.This steeper angle of the dark state light allows for the light trap tobe positioned closer to the DLP 402 so that the overall size of theupper module 202 can be reduced. The light trap can also be made largersince the light trap doesn't interfere with the field lens, thereby theefficiency of the light trap can be increased and as a result, straylight can be reduced and the contrast of the image perceived by the usercan be increased. FIG. 4 a provides a further illustration of examplegeometry associated with the light source, 404 the TIR wedge 418 andassociated thin air gap, and the corrective wedge 420 such that lightfrom the light source is reflected toward the DLP 402 and the imagelight 414 is transmitted in a direction along the optical axis for thefield lens.

FIG. 5 illustrates yet another embodiment of an upper optical module 202in accordance with the principles of the present invention. As with theembodiment shown in FIG. 4, the embodiment shown in FIG. 5 does notrequire the use of polarized light. The optical module 202 depicted inFIG. 5 is similar to that presented in connection with FIG. 4; however,the embodiment of FIG. 5 includes an off light redirection wedge 502with an associated thin air gap. As can be seen from the illustration,the off light redirection wedge 502 allows the image light 414 tocontinue generally along the optical axis toward the field lens and intothe lower optical module 204 (as illustrated). However, the off light504 is incident at the interface to the off light redirection wedge 502and associated thin air gap at an angle that is beyond the criticalangle (see Eqn 1) so that the off light 504 is reflected and isredirected substantially toward the side of the corrective wedge 420where it passes into the light trap. This configuration may allowfurther height compactness in the HWC because the light trap (notillustrated) that is intended to absorb the off light 504 can bepositioned laterally adjacent the upper optical module 202 as opposed tobelow it. There may be HWC mechanical configurations that warrant thepositioning of a light trap for the dark state light elsewhere and theillustration depicted in FIG. 5 should be considered illustrative of theconcept that the off light can be redirected to create compactness ofthe overall HWC. FIG. 5 a provides a further illustration of examplegeometry associated with the light source 404, the TIR wedge 418 andassociated thin air gap, the corrective wedge 420 and associated thinair gap and the off light redirection wedge 502 such that the off lightis reflected to the side by TIR conditions at the interface between thecorrective wedge 420 and the off light redirection wedge 502. The imagelight 414 is transmitted through the interfaces between the TIR wedge418, the corrective wedge 420 and the off light redirection wedge 502 sothat it exits in a direction along the optical axis of the field lens.

FIG. 6 illustrates a combination of an upper optical module 202 with alower optical module 204. In this embodiment, the image light projectedfrom the upper optical module 202 may or may not be polarized. The imagelight is reflected off a flat combiner element 602 such that it isdirected towards the user's eye. Wherein, the combiner element 602 is apartial mirror that reflects image light while transmitting asubstantial portion of light from the environment so the user can lookthrough the combiner element and see the environment surrounding theHWC.

The combiner 602 may include a holographic pattern, to form aholographic mirror. If a monochrome image is desired, there may be asingle wavelength reflection design for the holographic pattern on thesurface of the combiner 602. If the intention is to have multiple colorsreflected from the surface of the combiner 602, a multiple wavelengthholographic mirror may be included on the combiner surface. For example,in a three color embodiment, where red, green and blue pixels aregenerated in the image light, the holographic mirror may be reflectiveto wavelengths matching the wavelengths of the red, green and blue lightprovided by the light source. This configuration can be used as awavelength specific mirror where pre-determined wavelengths of lightfrom the image light are reflected to the user's eye. This configurationmay also be made such that substantially all other wavelengths in thevisible pass through the combiner element 602 so the user has asubstantially clear view of the surroundings when looking through thecombiner element 602. The transparency between the user's eye and thesurrounding may be approximately 80% when using a combiner that is aholographic mirror. Wherein holographic mirrors can be made using lasersto produce interference patterns in the holographic material of thecombiner where the wavelengths of the lasers correspond to thewavelengths of light that are subsequently reflected by the holographicmirror.

In another embodiment, the combiner element 602 may include a notchmirror comprised of a multilayer coated substrate wherein the coating isdesigned to substantially reflect the wavelengths of light provided bythe light source and substantially transmit the remaining wavelengths inthe visible spectrum. For example, in the case where red, green and bluelight is provided by the light source to enable full color images to beprovided to the user, the notch mirror is a tristimulus notch mirrorwherein the multilayer coating is designed to reflect narrow bands ofred, green and blue light that are matched to the what is provided bythe light source and the remaining visible wavelengths are transmittedto enable a view of the environment through the combiner. In anotherexample where monochrome images are provide to the user, the notchmirror is designed to reflect a narrow band of light that is matched tothe wavelengths of light provided by the light source while transmittingthe remaining visible wavelengths to enable a see-thru view of theenvironment. The combiner 602 with the notch mirror would operate, fromthe user's perspective, in a manner similar to the combiner thatincludes a holographic pattern on the combiner element 602. Thecombiner, with the tristimulus notch mirror, would reflect the “on”pixels to the eye because of the match between the reflectivewavelengths of the notch mirror and the color of the image light, andthe wearer would be able to see with high clarity the surroundings. Thetransparency between the user's eye and the surrounding may beapproximately 80% when using the tristimulus notch mirror. In addition,the image provided by the upper optical module 202 with the notch mirrorcombiner can provide higher contrast images than the holographic mirrorcombiner due to less scattering of the imaging light by the combiner.

FIG. 7 illustrates an embodiment of a combiner element 602 at variousangles when the combiner element 602 includes a holographic mirror.Normally, a mirrored surface reflects light at an angle equal to theangle that the light is incident to the mirrored surface. Typically thisnecessitates that the combiner element be at 45 degrees, 602 a, if thelight is presented vertically to the combiner so the light can bereflected horizontally towards the wearer's eye. In embodiments, theincident light can be presented at angles other than vertical to enablethe mirror surface to be oriented at other than 45 degrees, but in allcases wherein a mirrored surface is employed, the incident angle equalsthe reflected angle. As a result, increasing the angle of the combiner602 a requires that the incident image light be presented to thecombiner 602 a at a different angle which positions the upper opticalmodule 202 to the left of the combiner as shown in FIG. 7. In contrast,a holographic mirror combiner, included in embodiments, can be made suchthat light is reflected at a different angle from the angle that thelight is incident onto the holographic mirrored surface. This allowsfreedom to select the angle of the combiner element 602 b independent ofthe angle of the incident image light and the angle of the lightreflected into the wearer's eye. In embodiments, the angle of thecombiner element 602 b is greater than 45 degrees (shown in FIG. 7) asthis allows a more laterally compact HWC design. The increased angle ofthe combiner element 602 b decreases the front to back width of thelower optical module 204 and may allow for a thinner HWC display (i.e.the furthest element from the wearer's eye can be closer to the wearer'sface).

Light can escape through the combiner 602 and may produce face glow asthe light is generally directed downward onto the cheek of the user.When using a holographic mirror combiner or a tristimulus notch mirrorcombiner, the escaping light can be trapped to avoid face glow. Inembodiments, if the image light is polarized before the combiner 602, alinear polarizer can be laminated, or otherwise associated, to thecombiner 602 (for example, the polarizer can be laminated to the side ofthe combiner that is away from the user's eye), with the transmissionaxis of the polarizer oriented relative to the polarized image light sothat any escaping image light is absorbed by the polarizer. Inembodiments, the image light would be polarized to provide S polarizedlight to the combiner 602 for better reflection. As a result, the linearpolarizer on the combiner 602 would be oriented to absorb S polarizedlight and pass P polarized light. This provides the preferredorientation of polarized sunglasses as well as this orientation willabsorb light reflected from the surface of lakes and ponds. In apreferred embodiment, the polarizer is combined with a tristimulus notchmirror combiner.

If the image light is unpolarized, a microlouvered film such as aprivacy filter (for example 3M ALCF:http://products3.3m.com/catalog/us/en001/electronics_mfg/vikuiti/node_PSG4KNNLC2be/root_GST1T4S9TCgv/vroot_S6Q2FD9X0Jge/gvel_ZF5G3RNK7Bgl/theme_us_vikuiti_(—)3_(—)0/command_AbcPageHandler/output_html)can be used to absorb the escaping image light while providing the userwith a see-thru view of the environment. In this case, the absorbance ortransmittance of the microlouvered film is dependent on the angle of thelight, Where steep angle light is absorbed by the microlouvered film andlight at less of an angle is transmitted by the microlouvered film. Forthis reason, in an embodiment, the combiner 602 with the microlouverfilm is angled at greater than 45 degrees, as shown in FIG. 7 ascombiner 602 b, to the optical axis of the image light presented to theuser's eye (e.g. the combiner can be oriented at 50 degrees so the imagelight from the field lens is incident on the combiner at 40 degrees forexample. Where the combiner and the lower optical module 204 areoriented such that light for the see-thru view passes through thecombiner at an angle that is closer to normal incidence that the anglethat the image light is incident upon the combiner. In a preferredembodiment, the microlouvered film is combined with a holographic mirrorcombiner.

FIG. 8 illustrates another embodiment of a lower optical module 204. Inthis embodiment, polarized image light provided by the upper opticalmodule 202, is directed into the lower optical module 204. The imagelight reflects off a polarized mirror 804 and is directed to a focusingpartially reflective mirror 802, which is adapted to reflect thepolarized light. An optical element such as a ¼wave film located betweenthe polarized mirror 804 and the partially reflective mirror 802, isused to change the polarization state of the image light such that thelight reflected by the partially reflective mirror 802 is transmitted bythe polarized mirror 804 to present image light to the eye of thewearer. The user can also see through the polarized mirror 804 and thepartially reflective mirror 802 to see the surrounding environment. As aresult, the user perceives a combined image comprised of the displayedimage light overlaid onto the see-thru view of the environment.

Another aspect of the present invention relates to eye imaging. Inembodiments, a camera is used in connection with an upper optical module202 such that the wearer's eye can be imaged using pixels in the “off”state on the DLP. FIG. 9 illustrates a system where the eye imagingcamera 802 is mounted and angled such that the field of view of the eyeimaging camera 802 is redirected toward the wearer's eye by the mirrorpixels of the DLP 402 that are in the “off” state. In this way, the eyeimaging camera 802 can be used to image the wearer's eye along the sameoptical axis as the displayed image that is presented to the wearer.Wherein, image light that is presented to the wearer's eye illuminatesthe wearer's eye so that the eye can be imaged by the eye imaging camera802. In the process, the light reflected by the eye passes back thoughthe optical train of the lower optical module 204 and a portion of theupper optical module to where the light is reflected by the “off” pixelsof the DLP 402 toward the eye imaging camera 802.

In embodiments, the eye imaging camera may image the wearer's eye at amoment in time where there are enough “off” pixels to achieve therequired eye image resolution. In another embodiment, the eye imagingcamera collects eye image information from “off” pixels over time andforms a time lapsed image. In another embodiment, a modified image ispresented to the user wherein enough “off” state pixels are includedthat the camera can obtain the desired resolution and brightness forimaging the wearer's eye and the eye image capture is synchronized withthe presentation of the modified image.

The eye imaging system may be used for security systems. The HWC may notallow access to the HWC or other system if the eye is not recognized(e.g. through eye characteristics including retina or irischaracteristics, etc.). The HWC may be used to provide constant securityaccess in some embodiments. For example, the eye security confirmationmay be a continuous, near-continuous, real-time, quasi real-time,periodic, etc. process so the wearer is effectively constantly beingverified as known. In embodiments, the HWC may be worn and eye securitytracked for access to other computer systems.

The eye imaging system may be used for control of the HWC. For example,a blink, wink, or particular eye movement may be used as a controlmechanism for a software application operating on the HWC or associateddevice.

The eye imaging system may be used in a process that determines how orwhen the HWC 102 delivers digitally displayed content to the wearer. Forexample, the eye imaging system may determine that the user is lookingin a direction and then HWC may change the resolution in an area of thedisplay or provide some content that is associated with something in theenvironment that the user may be looking at. Alternatively, the eyeimaging system may identify different user's and change the displayedcontent or enabled features provided to the user. User's may beidentified from a database of users eye characteristics either locatedon the HWC 102 or remotely located on the network 110 or on a server112. In addition, the HWC may identify a primary user or a group ofprimary users from eye characteristics wherein the primary user(s) areprovided with an enhanced set of features and all other user's areprovided with a different set of features. Thus in this use case, theHWC 102 uses identified eye characteristics to either enable features ornot and eye characteristics need only be analyzed in comparison to arelatively small database of individual eye characteristics.

FIG. 10 illustrates a light source that may be used in association withthe upper optics module 202 (e.g. polarized light source if the lightfrom the solid state light source is polarized), and light source 404.In embodiments, to provide a uniform surface of light 1008 to bedirected towards the DLP of the upper optical module, either directly orindirectly, the solid state light source 1002 may be projected into abacklighting optical system 1004. The solid state light source 1002 maybe one or more LEDs, laser diodes, OLEDs. In embodiments, thebacklighting optical system 1004 includes an extended section with alength/distance ratio of greater than 3, wherein the light undergoesmultiple reflections from the sidewalls to mix of homogenize the lightas supplied by the solid state light source 1002. The backlightingoptical system 1004 also includes structures on the surface opposite (onthe left side as shown in FIG. 10) to where the uniform light 1008 exitsthe backlight 1004 to change the direction of the light toward the DLP302 and the reflective polarizer 310 or the DLP 402 and the TIR wedge418. The backlighting optical system 1004 may also include structures tocollimate the uniform light 1008 to provide light to the DLP with asmaller angular distribution or narrower cone angle. Diffusers includingelliptical diffusers can be used on the entrance or exit surfaces of thebacklighting optical system to improve the uniformity of the uniformlight 1008 in directions orthogonal to the optical axis of the uniformlight 1008.

FIGS. 10 a and 10 b show illustrations of structures in backlightoptical systems 1004 that can be used to change the direction of thelight provided to the entrance face 1045 by the light source and thencollimates the light in a direction lateral to the optical axis of theexiting uniform light 1008. Structure 1060 includes an angled sawtoothpattern wherein the left edge of each sawtooth clips the steep anglerays of light thereby limiting the angle of the light being redirected.The steep surface at the right (as shown) of each sawtooth thenredirects the light so that it reflects off the left angled surface ofeach sawtooth and is directed toward the exit surface 1040. Structure1050 includes a curved face on the left side (as shown) to focus therays after they pass through the exit surface 1040, thereby providing amechanism for collimating the uniform light 1008.

FIG. 11 a illustrates a light source 1100 that may be used inassociation with the upper optics module 202. In embodiments, the lightsource 1100 may provide light to a backlighting optical system 1004 asdescribed above in connection with FIG. 10. In embodiments, the lightsource 1100 includes a tristimulus notch filter 1102. The tristimulusnotch filter 1102 has narrow band pass filters for three wavelengths, asindicated in FIG. 11 c in a transmission graph 1108. The graph shown inFIG. 11 b, as 1104 illustrates an output of three different coloredLEDs. One can see that the bandwidths of emission are narrow, but theyhave long tails. The tristimulus notch filter 1102 can be used inconnection with such LEDs to provide a light source 1100 that emitsnarrow filtered wavelengths of light as shown in FIG. 11 d as thetransmission graph 1110. Wherein the clipping effects of the tristimulusnotch filter 1102 can be seen to have cut the tails from the LEDemission graph 1104 to provide narrower wavelength bands of light to theupper optical module 202. The light source 1100 can be used inconnection with a combiner 602 with a holographic mirror or tristimulusnotch mirror to provide narrow bands of light that are reflected towardthe wearer's eye with less waste light that does not get reflected bythe combiner, thereby improving efficiency and reducing escaping lightthat can cause faceglow.

FIG. 12 illustrates another light source 1200 that may be used inassociation with the upper optics module 202. In embodiments, the lightsource 1200 may provide light to a backlighting optical system 1004 asdescribed above in connection with FIG. 10. In embodiments, the lightsource 1200 includes a quantum dot cover glass 1202. Where the quantumdots absorb light of a shorter wavelength and emit light of a longerwavelength (FIG. 12 a shows an example wherein a UV spectrum 1202applied to a quantum dot results in the quantum dot emitting a narrowband shown as a PL spectrum 1204) that is dependent on the materialmakeup and size of the quantum dot. As a result, quantum dots in thequantum dot cover glass 1202 can be tailored to provide one or morebands of narrow bandwidth light (e.g. red, green and blue emissionsdependent on the different quantum dots included as illustrated in thegraph shown in FIG. 12 b where three different quantum dots are used. Inembodiments, the LED driver light emits UV light, deep blue or bluelight. For sequential illumination of different colors, multiple lightsources 1200 would be used where each light source 1200 would include aquantum dot cover glass 1202 with a single type of quantum dot selectedto emit at one of the desired colors. The light source 1200 can be usedin connection with a combiner 602 with a holographic mirror ortristimulus notch mirror to provide narrow bands of light that arereflected toward the wearer's eye with less waste light that does notget reflected.

Another aspect of the present invention relates to the generation ofperipheral image lighting effects for a person wearing a HWC. Inembodiments, a solid state lighting system (e.g. LED, OLED, etc), orother lighting system, may be included inside the optical elements of anlower optical module 204. The solid state lighting system may bearranged such that lighting effects outside of a field of view (FOV) ofthe presented digital content is presented to create an emersive effectfor the person wearing the HWC. To this end, the lighting effects may bepresented to any portion of the HWC that is visible to the wearer. Thesolid state lighting system may be digitally controlled by an integratedprocessor on the HWC. In embodiments, the integrated processor willcontrol the lighting effects in coordination with digital content thatis presented within the FOV of the HWC. For example, a movie, picture,game, or other content, may be displayed or playing within the FOV ofthe HWC. The content may show a bomb blast on the right side of the FOVand at the same moment, the solid state lighting system inside of theupper module optics may flash quickly in concert with the FOV imageeffect. The effect may not be fast, it may be more persistent toindicate, for example, a general glow or color on one side of the user.The solid state lighting system may be color controlled, with red, greenand blue LEDs, for example, such that color control can be coordinatedwith the digitally presented content within the field of view.

FIG. 13 a illustrates optical components of a lower optical module 204together with an outer lens 1302. FIG. 13 a also shows an embodimentincluding effects LED's 1308 a and 1308 b. FIG. 13 a illustrates imagelight 1312, as described herein elsewhere, directed into the upperoptical module where it will reflect off of the combiner element 1304,as described herein elsewhere. The combiner element 1304 in thisembodiment is angled towards the wearer's eye at the top of the moduleand away from the wearer's eye at the bottom of the module, as alsoillustrated and described in connection with FIG. 8 (e.g. at a 45 degreeangle). The image light 1312 provided by an upper optical module 202(not shown in FIG. 13 a) reflects off of the combiner element 1304towards the collimating mirror 1310, away from the wearer's eye, asdescribed herein elsewhere. The image light 1312 then reflects andfocuses off of the collimating mirror 1304, passes back through thecombiner element 1304, and is directed into the wearer's eye. The wearercan also view the surrounding environment through the transparency ofthe combiner element 1304, collimating mirror 1310, and outer lens 1302(if it is included). As described herein elsewhere, various surfaces arepolarized to create the optical path for the image light and to providetransparency of the elements such that the wearer can view thesurrounding environment. The wearer will generally perceive that theimage light forms an image in the FOV 1305. In embodiments, the outerlens 1302 may be included. The outer lens 1302 is an outer lens that mayor may not be corrective and it may be designed to conceal the loweroptical module components in an effort to make the HWC appear to be in aform similar to standard glasses or sunglasses.

In the embodiment illustrated in FIG. 13 a, the effects LEDs 1308 a and1308 b are positioned at the sides of the combiner element 1304 and theouter lens 1302 and/or the collimating mirror 1310. In embodiments, theeffects LEDs 1308 a are positioned within the confines defined by thecombiner element 1304 and the outer lens 1302 and/or the collimatingmirror. The effects LEDs 1308 a and 1308 b are also positioned outsideof the FOV 1305. In this arrangement, the effects LEDs 1308 a and 1308 bcan provide lighting effects within the lower optical module outside ofthe FOV 1305. In embodiments the light emitted from the effects LEDs1308 a and 1308 b may be polarized such that the light passes throughthe combiner element 1304 toward the wearer's eye and does not passthrough the outer lens 1302 and/or the collimating mirror 1310. Thisarrangement provides peripheral lighting effects to the wearer in a moreprivate setting by not transmitting the lighting effects through thefront of the HWC into the surrounding environment. However, in otherembodiments, the effects LEDs 1308 a and 1308 b may be unpolarized sothe lighting effects provided are made to be purposefully viewable byothers in the environment for entertainment such as giving the effect ofthe wearer's eye glowing in correspondence to the image content beingviewed by the wearer.

FIG. 13 b illustrates a cross section of the embodiment described inconnection with FIG. 13 a. As illustrated, the effects LED 1308 a islocated in the upper-front area inside of the optical components of thelower optical module. It should be understood that the effects LED 1308a position in the described embodiments is only illustrative andalternate placements are encompassed by the present invention.Additionally, in embodiments, there may be one or more effects LEDs 1308a in each of the two sides of HWC to provide peripheral lighting effectsnear one or both eyes of the wearer.

FIG. 13 c illustrates an embodiment where the combiner element 1304 isangled away from the eye at the top and towards the eye at the bottom(e.g. in accordance with the holographic or notch filter embodimentsdescribed herein). In this embodiment, the effects LED 1308 a is locatedon the outer lens 1302 side of the combiner element 1304 to provide aconcealed appearance of the lighting effects. As with other embodiments,the effects LED 1308 a of FIG. 13 c may include a polarizer such thatthe emitted light can pass through a polarized element associated withthe combiner element 1304 and be blocked by a polarized elementassociated with the outer lens 1302.

Another aspect of the present invention relates to the mitigation oflight escaping from the space between the wearer's face and the HWCitself. Another aspect of the present invention relates to maintaining acontrolled lighting environment in proximity to the wearer's eyes. Inembodiments, both the maintenance of the lighting environment and themitigation of light escape are accomplished by including a removable andreplaceable flexible shield for the HWC. Wherein the removable andreplaceable shield can be provided for one eye or both eyes incorrespondence to the use of the displays for each eye. For example, ina night vision application, the display to only one eye could be usedfor night vision while the display to the other eye is turned off toprovide good see-thru when moving between areas where visible light isavailable and dark areas where night vision enhancement is needed.

FIG. 14 a illustrates a removable and replaceable flexible eye cover1402 with an opening 1408 that can be attached and removed quickly fromthe HWC 102 through the use of magnets. Other attachment methods may beused, but for illustration of the present invention we will focus on amagnet implementation. In embodiments, magnets may be included in theeye cover 1402 and magnets of an opposite polarity may be included (e.g.embedded) in the frame of the HWC 102. The magnets of the two elementswould attract quite strongly with the opposite polarity configuration.In another embodiment, one of the elements may have a magnet and theother side may have metal for the attraction. In embodiments, the eyecover 1402 is a flexible elastomeric shield. In embodiments, the eyecover 1402 may be an elastomeric bellows design to accommodateflexibility and more closely align with the wearer's face. FIG. 14 billustrates a removable and replaceable flexible eye cover 1404 that isadapted as a single eye cover. In embodiments, a single eye cover may beused for each side of the HWC to cover both eyes of the wearer. Inembodiments, the single eye cover may be used in connection with a HWCthat includes only one computer display for one eye. Theseconfigurations prevent light that is generated and directed generallytowards the wearer's face by covering the space between the wearer'sface and the HWC. The opening 1408 allows the wearer to look through theopening 1408 to view the displayed content and the surroundingenvironment through the front of the HWC. The image light in the loweroptical module 204 can be prevented from emitting from the front of theHWC through internal optics polarization schemes, as described herein,for example.

FIG. 14 c illustrates another embodiment of a light suppression system.In this embodiment, the eye cover 1410 may be similar to the eye cover1402, but eye cover 1410 includes a front light shield 1412. The frontlight shield 1412 may be opaque to prevent light from escaping the frontlens of the HWC. In other embodiments, the front light shield 1412 ispolarized to prevent light from escaping the front lens. In a polarizedarrangement, in embodiments, the internal optical elements of the HWC(e.g. of the lower optical module 204) may polarize light transmittedtowards the front of the HWC and the front light shield 1412 may bepolarized to prevent the light from transmitting through the front lightshield 1412.

In embodiments, an opaque front light shield 1412 may be included andthe digital content may include images of the surrounding environmentsuch that the wearer can visualize the surrounding environment. One eyemay be presented with night vision environmental imagery and this eye'ssurrounding environment optical path may be covered using an opaquefront light shield 1412. In other embodiments, this arrangement may beassociated with both eyes.

Another aspect of the present invention relates to automaticallyconfiguring the lighting system(s) used in the HWC 102. In embodiments,the display lighting and/or effects lighting, as described herein, maybe controlled in a manner suitable for when an eye cover 1408 isattached or removed from the HWC 102. For example, at night, when thelight in the environment is low, the lighting system(s) in the HWC maygo into a low light mode to further control any amounts of stray lightescaping from the HWC and the areas around the HWC. Covert operations atnight, while using night vision or standard vision, may require asolution which prevents as much escaping light as possible so a user mayclip on the eye cover(s) 1408 and then the HWC may go into a low lightmode. The low light mode may, in some embodiments, only go into a lowlight mode when the eye cover 1408 is attached if the HWC identifiesthat the environment is in low light conditions (e.g. throughenvironment light level sensor detection). In embodiments, the low lightlevel may be determined to be at an intermediate point between full andlow light dependent on environmental conditions.

Another aspect of the present invention relates to automaticallycontrolling the type of content displayed in the HWC when eye covers1408 are attached or removed from the HWC. In embodiments, when the eyecover(s) 1408 is attached to the HWC, the displayed content may berestricted in amount or in color amounts. For example, the display(s)may go into a simple content delivery mode to restrict the amount ofinformation displayed. This may be done to reduce the amount of lightproduced by the display(s). In an embodiment, the display(s) may changefrom color displays to monochrome displays to reduce the amount of lightproduced. In an embodiment, the monochrome lighting may be red to limitthe impact on the wearer's eyes to maintain an ability to see better inthe dark.

Although embodiments of HWC have been described in language specific tofeatures, systems, computer processes and/or methods, the appendedclaims are not necessarily limited to the specific features, systems,computer processes and/or methods described. Rather, the specificfeatures, systems, computer processes and/or and methods are disclosedas non-limited example implementations of HWC. All documents referencedherein are hereby incorporated by reference.

We claim:
 1. A computer display stray-light suppression system for ahead-worn computer, comprising: a. An eye cover including an elasticmaterial with a perimeter, wherein the perimeter is formed tosubstantially encapsulate an eye of a person; and b. The eye coverincluding a magnetic attachment system adapted to removably andreplaceably attach to a perimeter of the head-worn computer to suppresslight emitted from a computer display in the head-worn computer.
 2. Thecomputer display stray-light suppression system for a head-worn computerof claim 1, wherein the magnetic attachment system includes a magnet ofa first polarization attached to the eye cover and a magnet of a secondpolarization attached to the head-worn computer.
 3. The computer displaystray-light suppression system for a head-worn computer of claim 1,wherein the magnetic attachment system includes a magnet attached to theeye cover.
 4. The computer display stray-light suppression system for ahead-worn computer of claim 1, wherein the magnetic attachment systemincludes a magnet attached to the head-worn computer.
 5. The computerdisplay stray-light suppression system for a head-worn computer of claim1, wherein the eye cover is adapted to cover one eye of the person. 6.The computer display stray-light suppression system for a head-worncomputer of claim 1, wherein the eye cover is adapted to cover both eyesof the person.
 7. The computer display stray-light suppression systemfor a head-worn computer of claim 1, further comprising a processor inthe head-worn computer adapted to detect when the eye cover is attachedto the head-worn computer.
 8. The computer display stray-lightsuppression system for a head-worn computer of claim 7, wherein theprocessor changes a lighting condition of the head-worn computer whenthe eye cover is attached to the head-worn computer.
 9. The computerdisplay stray-light suppression system for a head-worn computer of claim1, further comprising a front cover adapted to cover a front lens of thehead-worn computer to suppress stray light from escaping the front lens.10. The computer display stray-light suppression system for a head-worncomputer of claim 9, wherein the front cover substantially covers onefront lens of the head-worn computer.